This invention relates to a bloodless catheter. More particularly, this invention relates to a bloodless over-the-needle catheter.
Various types of over-the-needle catheters have been known for use as venipuncture devices and, particularly, for intravenous infusion purposes. Typically, these devices have been fabricated of a needle that is connected to a hub and a catheter that passes over the needle and is fixed as by a friction fit at an exposed end of the needle. The catheter is also fixed to a hub that receives the needle hub. Additional structure is also provided to form a closed chamber about the ends of the two hubs.
After implanting of the needle and catheter in a patient, the needle is usually removed while the catheter remains in place. A connection is then made between an I.V. line and the catheter in order to allow for the infusion of liquids and/or medicaments into the patient.
In almost all hospitals, there is a policy that once a catheter is in place and a connection made, that connection is never broken. With that as a design criteria, then there is no need for a bloodless catheter to have a reseal capability beyond the initial closure following the removal of the needle. In other words, there is a need only for the hub to somehow seal itself off from the outside environment when the needle is removed and then re-opened to allow fluid flow when a connection is made, e.g. by means of a male luer connector. The male luer connector is attached only once and never removed from the catheter hub. If per chance the male luer connector has to be removed in an emergency situation, then it would be permissible for blood to back flow through the catheter.
U.S. Pat. Nos. 5,330,435 and 5,234,410 describe different types of over-the-needle catheters which employ an elastomeric valve on a tube of the catheter to seal off the cannula of the catheter.
U.S. Pat. No. 5,211,634 describes a composite seal structure which is used in a coupling between a syringe and a line to a vein in a patient.
U.S. Pat. No. 5,487,728 describes the use of a seal having a resilient collapsible tubular portion and a septum at one end for sealing off a needle in a female luer connector.
Accordingly, it is an object of the invention to provide product which would meet these needs and be substantially less complicated, less costly to make and assemble than the previously known products.
Briefly, the invention is directed to a bloodless catheter comprised in part of a hub having a bore at a proximal end and a cannula fixed in and extending from an opposite distal end of the hub.
In accordance with the invention, a septum seal with a weakened central section is mounted in the bore of the hub in circumferentially sealed relation to prevent a flow of fluid from the cannula to the proximal end of the hub.
A means is also provided in the hub for forming a flow path through the weakened section of the seal in response to a relative movement between this means and this seal.
In use, a second means is provided for moving the first means relative to the seal in order to define a flow path through the seal.
In one embodiment, the means in the hub for forming a flow path is in the form of a tube which is mounted in the weakened section of the seal and which extends into the cannula. In addition, the means for moving the tube relative to the seal constitutes a male luer adaptor which can be slidably mounted in the bore of the hub in sealed relation and disposed concentrically about the tube. In this case, the forward end or nose of the adaptor engages and pushes the septum seal along the tube while the seal dilates about the slit in the weakened section of the seal.
In this embodiment, after the introducer needle and associated hub have been removed, the seal prevents any flow of blood from a patient through the hub.
In another embodiment, the means for forming a flow path through the weakened section of the seal is in the form of a piercing ring that is mounted on the seal for pushing through the weakened section of the seal in a direction towards the cannula in order to define a flow path through the seal. In this embodiment, a male luer adaptor may also be used as the means to move the piercing ring relative to the seal. In this case, the male luer adaptor is sized to engage and push the piercing ring through a slit in the septum seal in order to communicate the adaptor with the cannula.
Typically, in order to form an over-the-needle catheter, a needle hub is telescopically mounted in the bore of the hub while an introducer needle is fixed in the needle hub and extends through the cannula. In use, the introducer needle and catheter are introduced into a patient in the usual manner. Thereafter, the introducer needle and associated hub are withdrawn. At this time, the seal closes on itself to seal off the cannula from the proximal end of the first hub so that blood cannot flow from the patient out of the hub.
These and other objects and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings wherein: